This invention relates to the field of endoprostheses for the treatment of blood-vessel bifurcation stenosis.
This invention also relates to a purpose-built installation device.
It has already been suggested that stenosis found in coronary arteries be treated using endoprostheses formed from tubular structures perforated With a grid pattern of slits and consequently expandable following placement at the site of stenosis. In most cases these endoprostheses are expanded by inflating a balloon which is placed inside them and subsequently withdrawn.
Generally speaking, endoprostheses of this type may be said to have already given good service.
They are not, however, fully satisfactory.
The applicant has, in particular, observed that standard endoprostheses are not fully satisfactory when, as is frequently the case, there is stenosis at a blood-vessel bifurcation. In such cases, treatment using standard endoprostheses requires two separate endoprostheses. One of these is placed in each of the two vessels branching off from the bifurcation and their positioning in relation to each other is adjusted as finely as possible to ensure optimal cover of the bifurcation area.
A primary goal of this invention is to develop existing endoprostheses in order to facilitate and improve treatment of blood-vessel bifurcation stenosis.
This goal is attained by this invention through the use of an endoprosthesis comprising three tubular sections and two connectors, namely:
a proximal section;
a first distal section aligned at least approximately with the proximal section and intended for insertion into one of the vessels branching off from the bifurcation, this distal section being attached to the proximal section by means of a laterally positioned connector; and
a second distal section placed at the side of the first distal section and intended for insertion into the second vessel branching off from the bifurcation, the two distal sections having their proximal ends joined by the second connector.
In accordance with another advantageous feature of this invention, the distal end of the proximal section is chamfered and the proximal end of the second distal section is tapered at the other side of the second connector and fits into the chamfer in the proximal section.
The above-mentioned chamfered shapes and tapered ends may have a variety of embodiments. They may, in particular, be delimited by flat or curved surfaces.
Another important goal of this invention is to perfect the method of installing the above-mentioned endoprostheses.
According to this invention this goal is attained by using a double-balloon system, as follows:
a first balloon of suitable length for insertion into two approximately aligned sections of the blood vessel to be treated: the main stem and the first branching blood vessel, on either side of the bifurcation area respectively; and
a second balloon of suitable nature for insertion into the second blood vessel branching off from the bifurcation.
In accordance with another advantageous feature of the invention, the first balloon incorporates a lateral recess to be positioned facing the bifurcation area with a view to housing the proximal end of the second balloon.
In accordance with another advantageous feature of this invention, the distal portion of the first balloon located downstream of the recess is of smaller diameter than the proximal portion of the balloon located upstream of the recess.